Often, the solution is administered in what is called a drip, which means the medicine of any sort drips into the IV site at planned intervals, through a tube. In many cases people have a continuous drip, where medication or fluids go in at regular times until the bag of medicine or fluids is empty.
As you can see, muscle contraction is regulated by the level of calcium ions in the cytoplasm. In skeletal muscle, calcium ions work at the level of actin (actin-regulated contraction). They move the troponin-tropomyosin complex off the binding sites, allowing actin and myosin to interact.
Adenosine Triphosphate (ATP) is the immediate source of (chemical) energy for muscle contraction. Very little ATP is stored in muscle fibres (= ' muscle cells '), only enough to power muscle contractions for a few seconds. The ATP in muscles must be constantly replenished as it is used for various processes.